Small-Signal Model of the Two-Phase Interleaved Coupled-Inductor Boost Converter

A coupled-inductor dc-dc converter has several modes of operation in continuous-conduction mode (CCM) and discontinuous-conduction mode (DCM), and is quite complex. This paper presents the derivation of the complete small-signal model of a two-phase interleaved dc-dc boost converter utilizing a single-core coupled-inductor operating in both CCM and DCM. Several small-signal models are required to fully model the converter due to the complexity of the converter operating in DCM. The transfer functions are then derived from these small-signal models. The theoretical analysis is validated experimentally using frequency sweeps from a 1-kW prototype.